G90.81

Billable

Serotonin syndrome

G90.81 is the ICD-10-CM code for Serotonin syndrome. It is a billable, specific code valid for reimbursement.

Status
Billable
Chapter
G00-G99
Parent
G90.8
Edition
FY2026

G00-G99 Diseases of the nervous system

Includes

  • Serotonin toxicity

Code first

  • poisoning due to drug or toxin, such as:
  • linezolid (T36.8X- with sixth character 1-4)
  • monoamine oxidase inhibitors (T43.1X with sixth character 1-4)
  • selective serotonin and norepinephrine reuptake inhibitors [SSNRI] (T43.21 with sixth character 1-4)
  • selective serotonin reuptake inhibitors [SSRI] (T43.22 with sixth character 1-4)

Use additional code

  • code for adverse effect, if applicable, to identify drug, such as:
  • linezolid (T36.8X5)
  • monoamine oxidase inhibitors (T43.1X5)
  • selective serotonin and norepinephrine reuptake inhibitors [SSNRI] (T43.215)
  • selective serotonin reuptake inhibitors [SSRI] (T43.225)
  • code, if applicable, to identify:
  • disseminated intravascular coagulation (D65)
  • hypertensive crisis (I16.-)
  • metabolic acidosis (E87.2-)
  • shock, not elsewhere classified (R57.-)
  • toxic encephalopathy (G92.-)
  • ventricular tachycardia (I47.2-)

Frequently asked questions

What is ICD-10 code G90.81?
G90.81 is the ICD-10-CM code for "Serotonin syndrome". It falls under G00-G99 Diseases of the nervous system.
Is G90.81 a billable code?
Yes — G90.81 is a billable, specific ICD-10-CM code valid for reimbursement.

Source: CMS ICD-10-CM FY2026. For informational purposes only — not medical advice. See our medical disclaimer.

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